Refining oils



Patented Aug. 21, 1928.

UNITED STATES LOUIS BURGESS,

PATENT OFFICE.

OF BAYONNE, NEW JERSEY, ASSIGNOR TO STANDARD OIL DEVELOP- KENT COMPANY, A CORPORATION OF DELAWARE.

REFINING OILS.

No Drawing.

This invention relates to the art of refining oils or the like, and will be fully understood from the following description:

In refining oils heretofore, particularly in 5 the making of white oil products and fancy lubricating oils b the use of fuming sulfuric acid, it has een customary to add the required acid in a number of successive treatments. At each treatment the acid enters into reaction with constituents in the oil, with the formation of products which separate out as a heavy sludge and are drawn oil from the oil. This sludge has been found to largely consist of hydrocarbon-sulfonic acids relal5 tivelyinsoluble in petroleum but soluble in water. At the same time certain products are formed Which remain in solution in the oil, and in special instances measures have been taken at the conclusion of the acid treatments to remove the compounds remaining in solution in the oil. These compounds also have been found to be hydrocarbon-sulfonic acids, but of different characteristics from those occurring in the sludge. The sludge acids have a characteristic green appearance in the free condition and a dark brown appearance when combined with ammonia or alkalies. The oil-soluble acids are brown in the free state, and pale yellow to brown when combined with ammonia or alkalies.

I have discovered that these oil-soluble sulfonic compounds are capable of engaging in further reactions with sulfuric acid; and by removing the oil-soluble sulfonic compounds 85 in each case before further adding sulfuric acid a corresponding increase in acid efficiency and an increased yield of the oil soluble sulfonic compounds may be obtained.

In proceeding in accordance with the present invention, the oil to be treated is subjected to successive treatments with strong sulfuric acid, for example fuming sulfuric acid, in dumps of about 5% to 10% of acid 7 to each treatment, and after each such treatment the sludge is settled out and drawn off and the oil is then subjected to agents to remove the compounds dissolved in the oil. As such a ent I prefer to employ an alcohol. This mayie any of the available commercial a0 alcohols, for example methyl, ethyl or isopropyl or mixtures of two or more of such.

It will of course be understood that sufficient water should be present in the alcohol to prevent its dissolving to any considerable extent 6 in the oil. I preferably employ the alcohol 1923. Serial No. 651,435.

diluted with about by volume of water. The oil is agitated withthe alcohol, preferably though not necessarily with a simultaneous or preliminary neutralization of the oil-soluble sulfonic acids by caustic soda or ammonia. The alcoholic solution is then settled out of the oil and withdrawn. This treatment may be repeated until the desired extraction has been obtained. The oil is then settled and preferably blown or steamed substantially free of any entrained alcohol and 1s again treated with sulfuric acid and then extracted to remove the sulfonic compounds from the oil, and so on until the desired amount of acid treatment has been given.

As an illustrative example: A distillate from a coastal crude petroleum and having a gravity of 22.6" B. and viscosity of 161 seconds Saybolt at 100 F. was treated with four 9% dumps of fuming sulfuric acid and after each dump and agitation the sludge was drawn off and the oil was extracted with an aqueous isopropyl alcohol containing about 50% of water and containing also caustic soda for neutralization. The alcohol after thorough agitation was settled out and drawn ofl and the oil was blown substantially free of alcohol and water each timebefore the next dump of acid.

Although this process is particularly desirable in the making of white oil products and high grade lubricating oils with use of fuming acid, its utility is not confined to these, but may be realized in proportion where applied with any oil product or the like in which successive treatments with sulfuric acid of sufiicient strength to produce oil-soluble sulfur-containing compounds are employed.

While I have referred more particularly to alcohols as extracting agent for the oilsoluble compounds, it will be understood that the invention contemplates the use of any convenient solvent for this purpose, and in its broader aspects the use of any suitable means for separating'the oil-soluble compounds before further treating with acid.

What I claim is:

1. The improvement in the art of refining hydrocarbon oils, which comprises repeatedly treating the oil with fuming sulfuric acid in the proportion of 510%, whereby sludge and oil-soluble sulfur containing compounds are formed, and after each treatment with 5 to 10% of fuming sulphuric acid separating the sludge, and after each sludge separation subjecting the oil to the action of caustic soda and an aliphatic monohydric alcohol, and removing from the oil the alcohol solution containing dissolved oil-soluble sulfur compounds.

2. The improvement in the art of refining hydrocarbon oils, which comprises repeatedl treating the oil with fuming sulfuric aci whereby sludge and oil-soluble sulfur-containing compounds are formed, and after each treatment separating the sludge and subjecting the oil to the action of an aliphatic monohydric alcohol to dissolve the oil-soluble sulfur compounds, and removing such compounds from the oil.

3. The improvement in the art of refining hydrocarbon oils, which comprises rcpeatcdly treating the oil with fuming sulphuric acid whereby oil soluble sulphur-containing compounds are produced, and after each such treatment separating oil the sludge and sub jecting the oil .to the action of a secondary aliphatic alcohol and an alkali.

LOUIS BURGESS 

